add a background process to spot celery hangs and reload the worker pool

see: https://github.com/ansible/tower/issues/2085

installer/roles/image_build/files/supervisor_task.conf

@@ -15,6 +15,18 @@ stdout_logfile_maxbytes=0
 stderr_logfile=/dev/stderr
 stderr_logfile_maxbytes=0
 
+[program:celery-watcher]
+command = /usr/bin/awx-manage celery_watcher
+directory = /var/lib/awx
+environment = LANGUAGE="en_US.UTF-8",LANG="en_US.UTF-8",LC_ALL="en_US.UTF-8",LC_CTYPE="en_US.UTF-8"
+autostart = true
+autorestart = true
+stopwaitsecs = 5
+stdout_logfile=/dev/stdout
+stdout_logfile_maxbytes=0
+stderr_logfile=/dev/stderr
+stderr_logfile_maxbytes=0
+
 [program:callback-receiver]
 command = awx-manage run_callback_receiver
 directory = /var/lib/awx
@@ -38,7 +50,7 @@ stderr_logfile=/dev/stderr
 stderr_logfile_maxbytes=0
 
 [group:tower-processes]
-programs=celery,callback-receiver,channels-worker
+programs=celery,celery-watcher,callback-receiver,channels-worker
 priority=5
 
 # TODO: Exit Handler